This blog is to provide a forum for students enrolled in Systems Management Course at IIIT-Delhi to have a meaningful discussion related to the course.

Wednesday, November 10, 2010

Abhimanyu Khanna

Hi guys . I would be covering all about proxies in this blog .

so

What is a Proxy Server?
A proxy server is a kind of buffer between your computer and the Internet resources you are accessing. The data you request come to the proxy first, and only then it transmits the data to you. I know many are looking for IP Maskers or Scramblers, but honestly, it aint real easy for the simple fact that any website that you visit needs your IP to send the info packets too. If its scrambled, you will get alot of errors and crazy redirects :P My solution? Read on........... for a good list of Proxy servers try here&gt;&gt; http://www.multiproxy.org/

Why do I need to use proxy servers?
Transfer speed improvement. Proxy servers accumulate and save files that are most often requested by thousands of Internet users in a special database, called “cache”. Therefore, proxy servers are able to increase the speed of your connection to the Internet. The cache of a proxy server may already contain information you need by the time of your request, making it possible for the proxy to deliver it immediately.
Security and privacy. Anonymous proxy servers that hide your IP address thereby saving you from vulnerabilities concerned with it.
Sometimes you may encounter problems while accessing to web server when server administrator restricted access from your IP or even from wide IP range (for example restricting access from certain countries or geographical regions). So you try to access those pages using an anonymous proxy server.

What is a public proxy server?
It is a proxy server which is free and open for everybody on the Internet. Unfortunately most of them are not anonymous.
Free service trying to provide list of public HTTP proxy servers. Usually provide small list of proxies with low percent of functioning servers due to hosting restrictions on CPU time (they simply can't allow themselves to check many proxies every second especially in parallel).

The Solution?
When using an anonymous proxy server you don’t give a anybody chance to find out your IP address to use it in their own interests. ;) If there is a need to make an (inner) proxy connect to the outside world via another (outer) proxy server, you can use the same environment variables as are used to redirect clients to the proxy to make inner proxy use the outer one:
http_proxy
ftp_proxy
gopher_proxy
wais_proxy
E.g. your (inner) proxy server's startup script could look like this:
#!/bin/sh
http_proxy=http://outer.proxy.server:8082/
export http_proxy
/usr/etc/httpd -r /etc/inner-proxy.conf -p 8081

This is a little ugly, so there are also the following directives in the configuration file:
http_proxy http://outer.proxy.server/
ftp_proxy http://outer.proxy.server/
gopher_proxy http://outer.proxy.server/
wais_proxy http://outer.proxy.server/